None consented debit order ( guardriask)

Guard risk is debiting money from my account without my consent. It's been 3 month's now. I didn't know anything about this company until I contacted Nedbank. I had to pay R75 to block 3rd debit. But guard risk changed their reference to debit again this month. And apparently due to their mandate I cannot even reverse the debit. I tried calling the number which I got from Google so I can ask them to stop debiting my account but one just didn't go through and the other just kept on ringing. I don't know what to do anymore cause the R167 that they are taking every month I could do something's better about it than to pay the insurance that I don't even have policy nu of which I can't even claim what ever they specialise with. Nedbank blocked it again but it's not guaranteed. Does this mean Nedbank has to now loose a client over this?